Industrial controllers are special-purpose computers utilized for controlling industrial processes, manufacturing equipment, and other factory automation, such as data collection or networked systems. One type of industrial controller at the core of an industrial control system is a logic processor such as a Programmable Logic Controller (PLC) or Personal Computer (PC) based controller. Programmable Logic Controllers for instance, are programmed by systems designers to operate manufacturing processes via user-designed logic programs or user programs. The user programs are stored in memory and generally executed by the PLC in a sequential manner although instruction jumping, looping and interrupt routines, for example, are also common. Associated with the user program are a plurality of memory elements or variables that provide dynamics to PLC operations and programs.
Connected to the PLC are Input/Output (I/O) devices. I/O devices provide a connection to the PLC for both automated data collection devices such as limit switches, photoeyes, load cells, thermocouples, etc. and manual data collection devices such as keypads, keyboards, pushbuttons, etc. Differences in PLCs are typically dependent on the number of Input/Output (I/O) they can process, amount of memory, number and type of instructions and speed of the PLC central processing unit (CPU).
Another type of industrial controller at the core of an industrial control system is the process controller of a Distributed Control System (DCS). The process controller is typically programmed by a control engineer for continuous process control such as an oil refinery or a bulk chemical manufacturing plant. The control engineer configures control elements such as Proportional-Integral-Derivative (PID) control loops to continuously sample the I/O data, known as the process variable, from the process, compare the process variable to a configured set point and output an error signal, proportional to the difference between the set point and the process variable, to the control device. The control device then adjusts the element controlling the process property, such as a valve in a pipe for flow control or a heating element in a distillation column for temperature control, in an attempt to minimize the error signal. As the DCS name implies, many process controllers are distributed around the process and are communicatively coupled to each other forming the overall control system.
Connected to the process controller are similar types of I/O devices as connected to the PLC and additionally, intelligent I/O devices more common to the process control industry. These intelligent devices have embedded processors capable of performing further calculations or linearization of the I/O data before transmission to the process controller.
A visualization system is connected to the industrial controller providing a human-friendly window into the process instrumented for monitoring or control. The user of a visualization system configures one or more graphical displays representing some aspect of the process the industrial controller is controlling or monitoring. The graphical displays each contain a user configured number of data values collected from the I/O connected to the industrial controller and considered by the user as relevant to the particular graphical display or process area of interest.
As time passes and the user experiences an escalating number of issues of erratic or poor product quality or production downtime, the user configures additional graphical displays including more I/O data values collected by the industrial controller from the I/O until so many graphical displays and data values are available that the visualization system becomes difficult to navigate and unwieldy to diagnose process problems. The advance of technology with respect to visualization system capacity in terms of both number of graphical displays and number of I/O data values supported has exacerbated this problem leading to market pressure to design visualization systems more efficient in their ability to present data representations to the user of the visualization system.